Difference between revisions of "AY Honors/Lapidary/Answer Key"
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==6. What is a template, and how is it used? == | ==6. What is a template, and how is it used? == | ||
==7. What is a cabochon, and what is the usual thickness of the slab from which it is made? == | ==7. What is a cabochon, and what is the usual thickness of the slab from which it is made? == | ||
| + | A cabochon is a gemstone which has been shaped and polished as opposed to faceted. The resulting form is usually a convex top with a flat bottom. Cutting "en cabochon" is usually applied to opaque gems, while faceting is usually applied to transparent stones. Hardness is also taken into account as softer gemstones with a hardness lower than 7 on the Moh's hardness scale are easily scratched, mainly by silicon dioxide in dust and grit. This would quickly make translucent gems unattractive. Instead they are polished as cabochons, making the scratches less evident. | ||
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| + | The one notable exception to this is the case of asteriated stones such as star sapphires and chatoyant stones such as cat's eye chrysoberyl, where a domed cabochon cut is used to show the star or eye, which would not be seen in a faceted cut. | ||
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| + | Cabochons are usually cut from slabs ranging from one to three eighths of an inch thick (3 to 10 mm). | ||
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==8. How do you decide the best angle or position to slab a specimen? == | ==8. How do you decide the best angle or position to slab a specimen? == | ||
==9. Explain two methods of wet sanding while shaping and polishing the rock. == | ==9. Explain two methods of wet sanding while shaping and polishing the rock. == | ||
Revision as of 04:16, 17 January 2008
1. Name four safety precautions to be taken when sawing rocks.
2. Name two types of diamond saw lubricating and cooling solutions and their purpose.
3. Explain how a diamond saw cuts rocks, how it gets dull, and how it can be sharpened.
4. Describe the five basic steps to follow in bringing a slab or a flat surface to a polish.
5. What important precaution should be taken between each stage of grinding and sanding?
6. What is a template, and how is it used?
7. What is a cabochon, and what is the usual thickness of the slab from which it is made?
A cabochon is a gemstone which has been shaped and polished as opposed to faceted. The resulting form is usually a convex top with a flat bottom. Cutting "en cabochon" is usually applied to opaque gems, while faceting is usually applied to transparent stones. Hardness is also taken into account as softer gemstones with a hardness lower than 7 on the Moh's hardness scale are easily scratched, mainly by silicon dioxide in dust and grit. This would quickly make translucent gems unattractive. Instead they are polished as cabochons, making the scratches less evident.
The one notable exception to this is the case of asteriated stones such as star sapphires and chatoyant stones such as cat's eye chrysoberyl, where a domed cabochon cut is used to show the star or eye, which would not be seen in a faceted cut.
Cabochons are usually cut from slabs ranging from one to three eighths of an inch thick (3 to 10 mm).
